Despite being a series that would likely fit the virtual reality format quite well (with it being first-person and displaying all player information in the form of a helmet UI), Halo has never explored this area of gaming. But, if you've been searching for a way to improve the immersive qualities of your adventures with Master Chief, we have some good news for you.
Modder LivingFray has created a VR mod for Halo: Combat Evolved that allows players to experience the campaign in a VR format. It's a mod for the 2003 PC original release of the game and is not compatible with Halo: The Master Chief Collection, but what it does offer is two-handed aiming, motion controlled flashlight, melee, and crouching, a floating crosshair, 6DoF synced stereo view, weapon aiming, and grenade aiming, and tracked controllers too.
The mod is available to download via GitHub, and you can even see it in action in this epic video from LunchAndVR (thanks, UploadVR).